Two-hand control for the supply of pneumatic pressure to pressureresponsive devices



May 11, 1954 c. .1. KlRK ETAL 2,678,027

TWO-HAND CONTROL FOR THE SUPPLY OF PNEUMATIC PRESSURE TO PRESSURE-RESPONSIVE DEVICES Filed 001;. 31, 1952 2 Sheets-Sheet l QM/11607088 CfJ. MM 4 C. D. P SMHLLPEICE y 1954 c. J. KIRK ET AL 2,678,027

TWO-HAND CONTROL FOR THE SUPPLY OF PNEUMATIC PRESSURE TO PRESSURE-RESPONSIVE DEVICES Filed Oct. 31, 1952 2 Sheets-Sheet 2 Patented May 11, 1954 TWO-HAND CONTROL FOR THE SUPPLY OF PNEUMATIC PRESSURE TO PRESSURE- RESPONSIVE DEVICES Colin John Kirk and Cosby Donald Philipps Smallpeice, Richmond, England, assignors to Smallpeice Limited, Richmond, England Application October 31, 1952, Serial No. 318,128

Claims priority, application Great Britain October 31, 1951 3 Claims.

The invention-relates to a two-hand control for the supply of pneumatic pressure to a pressure-responsive device such, for instance, as a pneumatic piston and cylinder arrangement or a pneumatic pressure-operated main valve in a pneumatic pressure supply line.

The object of the invention is a control of this kind which requires a deliberate act of an operator and is less subject to accidental operation than controls at present in use.

According to the invention the control includes a reservoir which is connected to a supply of compressed gas when the movable members of two control valves, connected in series between the reservoir and the supply, are in one position,

and which discharges to the pressure-responsive device through a path which is only established when both movable members are operated substantially simultaneously to an alternative position, the movement to the alternative position of one only of the two movable valve members connecting the reservoir to exhaust. Preferably the movable members of both control valves are biassed to the position in which the reservoir is fed from the supply and are independently manually operable (for example, by push-button type controls) for establishing the said path.

In the drawings:

Figure 1 is a diagram illustrating the application of a control, according to the invention, to actuate a servo-operated valve connected in the supply to a double-acting, pneumatic piston and cylinder arrangement, and it'also shows a means for automatically returning the piston at the end of a forward stroke;

Figure 2 is a similar diagram, but showing the I4 and I5, and a double-acting piston and cylin- C der arrangement, to be controlled, at l5, H. The valve I l is shown biassed to the position in which it had previously supplied air through pipes I3 and for returning the piston ll after a forward' stroke; the piston, in assuming the fully returned position shown, having expressed the air in front of it through the pipes 2i and 22 and an exhaust passage of the valve.

The control valves I4 and I5 (which are of a push-button type) are shown in the positions in which they are set by their biasses, with internal passages permitting pressure air from the supply I2 to charge the reservoir l3 through pipes 26, TI, 28, 29 and 30. When both control valves are operated simultaneously (or substantially so) against their biasses they connect the reservoir through pipes 35, 3|, 32 and 33 to actuate the servo-operated valve l l, against its bias, for connecting the supply 2 to the rear of the cylinder [5, through pipes 22 and 2|, for giving the piston a forward stroke during which it expels the air in front of it through the pipes 20 and I9 and through an exhaust passage of the valve II.

The construction and functioning of the control valves [4, 15 will now be described. It will be seen that the valve [4, which is shown in the position for charging the reservoir, has two pairs of ports 34, 35 and 36, 31 with which coact a movable valve member 33 which can be slid by a push-button 39 against a biassing spring 40. The valve [5 has two ports 4|, 42 on one side, and three ports 43, 44 and 45 on the opposite side of a movable member 46 which also can be slid by a push-button 41 against a blessing spring 48.

In the position shown the ports 4| and 43 of the valve [5 are in communication through an annular space between lands 43 and 5B of the valve member 43, and the ports 34 and 35 of the valve l4 are in communication through a similar annular space between lands 5| and 52 of the valve member 38. In these conditions the pressure air in pipe 2? is fed through pipes 28, 29 and 33 to charge the reservoir. It will be noted that a further land 53 on valve member 38 is interrupting a communication between ports 36 and 31 of valve l4, and that ports 42 and 45 of valve l5 communicate with an exhaust pipe 54 through an annular space between lands 55 and 55 on the valve member 46. Thus the pipe 33 is in communication with the exhaust pipe for permitting the servo-operated valve ll (presently to be described) to recover the position into which it is biassed.

If both push-buttons 39 and 41 are operated simultaneously, the land 52 of valve [4 is moved to interrupt the communication between ports Hand 35, and the ports 35 and 3'. are put into communication through an annular space bctween the land 53 and a further land 37 of the valve member 38; and as regards valve I5 the communication between ports 46 and 43 will be interrupted by the land 50, and the communication between ports 42 and 35 will be interrupted by the land 55. In these conditions the compressed air in the reservoir can leave through pipes 3|, 32 and 33 to actuate the servo-operated valve I I against the bias for connecting the supply line to effect the forward stroke of the piston I1, and the end of the pipe 28 adjacent the valve I5 is put into communication with the exhaust pipe 54 through ports M and 44 and an annular space between lands 58 and 55.

Should push-button 39 only be operated the pipe 32 will still be in communication with the exhaust pipe 54 and the compressed air will not be delivered through pipe 33 for actuating the servooperated valve II; also the movement of land 52 of valve I4 will cut off the supply from the pipes 2! and 28 to the reservoir.

On the other hand should push-button 41 only be operated, the compressed air in the reservoir would pass through the pipe 28 to the exhaust pipe 54 through the annular space between lands 50 and 55, and the pressure in the pipe 27 would be held between lands 49 and 50.

The servo-operated valve II is shown as comprising a body 60 which is externally rectangular and contains a cylindrical, ported liner BI, there being lateral exhaust passages 62 and 83 between the ends of the liner and a cover 64 and a base 5, respectively. The body 68, has, on one side of the liner, a bore I2a communicating with the supply line I 2, and on the other side it has bores 22a and I9a respectively communicating with the pipes 22 and I9 for supplying the piston and cylinder arrangement. The movable member 66 of the valve has a piston-like portion 6! working in a bore of the cover 64 and the latter has a port 32a communicating with pipe 33. In the position shown a land 69 of the valve member is interrupting a communication between bores I2a and 22a, and a land I8 is establishing a communication between bores I2a and I9a, the communication being through ports II in an external annular groove I2 of the liner which is fed from the bore I2a, and ports I3 in a similar groove I4 of the liner and communicating with the bore I9a. In this position the valve II is supplying the compressed air through pipes I9 and for efiecting the return stroke of the piston H, the pipe 2I leading to the other end of the cylinder being connected, through the bore 22a and ports I II] in another annular groove of the liner, to the exhaust passage 63.

When both push-buttons 39 and 41 are oper ated the resultant pressure in pipe 33 displaces the valve member 56 of valve I I against a biassing spring I5, the latter being in a bore of the valve member 66 and reacting on a pin I6 which is fast with the base 65 and guides the valve member 66. In the new position, the bores I2a and 22a are put into communication through the annular space between lands E9 and ID for effecting the forward stroke of the piston I1, and the bore I9a is connected to the exhaust space 62.

When the piston II reaches the end of its forward stroke and the supply pressure consequently builds up behind it in the pipe 85, it can be arranged for a pressure-operated valve 80 to be operated for putting pipe 33 into communication, through a branch pipe 68, with an exhaust outlet 8|, whereby to initiate the return stroke of the piston. For this purpose the supply pressure can be fed, from the pipe 26 and a pipe 33, to a valve 84 containing a pressure responsive element which controls a communication to a pipe 86 leading to the valve 80. It is arranged for the pressure responsive element of the valve 84 to be acted on, through the pipe 85, by the 4 built-up pressure to operate the valve 88 by air delivered through the pipe 86.

The valves 88 and 84 can be of any suitable known kind, but functional examples are shown in the drawings, the means by which the settings of the valves could be adjusted not being shown. The valve is shown as having a plunger II2 which is to be depressed against a spring I I4 by the preponderant pressure acting through the pipe 86 for establishing a communication between the branch pipe 68 and the exhaust outlet 8|, the valve 84 having a plunger IIB which is held against an abutment I20 by a spring H8 in a position in which the pipe 88 communicates with an exhaust outlet I22. The plunger is depressed by a predetermined preponderance of the pressure in pipe 85 over the spring pressure to place the pipes 83 and 86 in communication for operating valve 80.

Figure 2 shows an adaptation of the dual pushbutton control, described above, to the operation of a single-acting piston and cylinder arrangement I6a, IIa, the piston being biassed to the returned position by a spring 90. In this application the servo-operated valve II is urged by its bias to cut off the supply through a pipe 9| to the cylinder, and to put the said pipe in communication with an exhaust opening like 62 or B3 of the valve. Valves 88, 82 and 84 are provided for initiating the return stroke of the piston when the pressure at the end of the forward stroke builds up.

Another application of the control to a singleacting piston and cylinder arrangement is shown in Figure 3, but instead of the return stroke being initiated by valves 80, 82 and 84, there is a valve I00 which has an arm IOI operated by a cam I02, driven from a part moving with the piston I 61), for putting pipe 33 into communication with an exhaust port I83 through a pipe I04.

Conveniently, and as shown in Figure 1, the various valves can be arranged in a box of which the outline is indicated at I30.

The control arrangement of the invention can be applied as a safety measure, for the operation of the clutch of a mechanical press or for delivering compressed air to operate a pneumatic press, the provision of separate push-button controls for operating the two control valves ensuring that the press shall only be operated after a deliberate two-fold simultaneous (or substantially simultaneous) action by an operator. Obviously, however, the control of the invention can be applied to other uses, not necessarily as a safety measure, and the valves I4 and I5 could be arranged for mechanical actuation (e. g., by cams) instead of manually.

What we claim as our invention and desire to secure by Letters Patent of the United States is:

1. A two-hand control for a supply of pneumatic pressure to a pressure-responsive device, including a reservoir, two control valves each having a manually-movable member, said movable members operable to alternative positions in which different through-passages are established through the associated valves, respective said through-passages of said valves which are selected when the movable member of each control valve is in a predetermined position for connecting the reservoir to the supply of pneumatic pressure through the two control valves connected in series, means forming a connection from between the two control valves to the pressure-responsive device, a communication containing one of said control valves and extending from said reservoir to said connection, said connection being cut-off from said reservoir and open to exhaust when said movable members are in said predetermined positions, and other respective said through-passages of said valves which are selected when the movable members of said control valves are in opposite predetermined positions toestablish a communication from said reservoir to said pressure-responsive device through said connection, such that said connection to said pressure-responsive device will be established only when both said movable members are operated substantially simultaneously to said opposite predetermined positions, and so that movement of only one of said movable members to its said opposite position will connect the reservoir to exhaust.

2. A control for a supply of pneumatic pressure to a pressure-responsive device, including a reservoir, two control valves each having a movable member which is biassed to a predetermined position and is manually operable to an alternative position, each of the movable members controlling two independent passages through the associated control valve, means connecting the supply of pneumatic pressure to one of the passages of one of the control valves, which passage is open when the movable member of said one control valve is in said predetermined position, a pipe line connecting said one passage of said one control valve to one of the passages of the other control valve, which latter passage is open when the movable member of said other control valve is in said predetermined position, means connectin said open passage of said other control valve to said reservoir, a second pipe line interconnecting the second passages of said control valves, the second passage of said one control valve being open and connected to exhaustwhen the movable member of said one control valve is in said predetermined position, the second passage of said other control valve connecting said second pipe line to the reservoir but being closed when the movable member of said other control valve is in said predeterminedposition, and means connecting said second pipe line to the pressure-responsive device, the control valves being such that, when the movable members of both are operated to their alternative positions, the said one passage of said one control valve will be closed and the adjacent end of said first-mentioned pipe line will be opened to exhaust, the second passage of said one valve will be closed, said one passage of said other control valve will be closed, and the second passage of said other control valve will be opened.

3. A control, according to claim 2, and including a pneumatic pressure-consuming means, the pressure-responsive device being a servo valve having connections whereby, when it is energized from the reservoir, it will directly connect the supply of pneumatic pressure to the pressureconsuming means.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,996,231 Daly Apr. 2, 193-5 23%,329 Davis Apr. 18, 1944 2,618,931 Cantley Nov. 25, 1952 

